The present invention relates to an intake device of an outboard motor having an improved structure.
An outboard motor is usually used under a relatively clean environment, and accordingly, atmosphere is directly taken as an intake air for an engine of the outboard motor without passing through an air cleaner. The air cleaner is provided with a function of a silencer for reducing noise which is caused at the air intake time, so that the outboard motor is equipped with a silencer for the intake system as intake noise silencing device in place of the location of the air cleaner.
However, in the structure of the engine of the outboard motor provided with no air cleaner, noise generated in the engine is reversely transferred in an (air) intake system and reaches inside the silencer in which the noise is increased, which is undesirable matter.
The present invention was conceived in view of the problem or defect mentioned above and an object of the present invention is therefore to provide an intake system of an outboard motor having an improved structure for reducing a noise generated in the outboard motor engine.
This and other objects of the present invention can be achieved by providing, in one aspect, an intake device of an outboard motor in which a throttle body is connected to an upstream side of an intake manifold connected to an intake port formed to a cylinder head of an engine and a silencer is connected to an upstream side of the throttle body, wherein a noise reduction device is disposed between a connecting portion of the throttle body and the silencer.
In a preferred embodiment of this aspect, the noise reduction device comprises a baffle plate formed from a plate member so as to provide a hyperbolic curve shape in section. The noise reduction device is provided with an intake opening.
In a more specific aspect, there is provided an intake device of an outboard motor which comprises:
an intake manifold connected to an intake port of an engine of an outboard motor;
a throttle body connected to an upstream side of the intake manifold;
a silencer connected to an upstream side of the throttle body; and
a noise reduction device disposed to the connecting portion between the throttle body and the silencer.
In a preferred embodiment, the noise reduction device comprises a baffle plate formed from a plate member so as to provide a hyperbolic curve shape in section. A plurality of intake openings are formed to the baffle plate.
Furthermore, an intake tube is disposed upstream side of the throttle body, the throttle body and the silencer are connected with the intake tube being disposed inside the silencer, and the noise reduction device is disposed at an upstream side end of the intake tube. The noise reduction device comprises a baffle plate formed from a plate member so as to provide a hyperbolic curve shape in section and a plurality of intake openings are formed to an outer peripheral surface of the intake tube.
According to the present invention of the characters mentioned above, since the noise reduction device is arranged to the connecting portion of the throttle body and the silencer, the engine noise such as intake pulsation noise can be reduced. Furthermore, the noise reduction device may be composed of a baffle plate formed from a plate member so as to provide a hyperbolic curve shape in section, so that both the noise shielding function and intake function can be achieved at the same time.
The nature and further characteristic features of the present invention will be made clear from the following descriptions made with reference to the accompanying drawings.